“Our most valuable and most instructive materials in the history of man are treasured up in India.”

Speech to the Canadian Club in Toronto (6 August 1927), quoted in Our Inheritance (London: Hodder and Stoughton, 1938), p. 79.
1927
Context: I may confess to men here, of a stock so largely English, that our English intelligence is sometimes apt to be despised by nations that think they are quicker-witted than we are. Our most valuable real estate is our character— its steadiness, its reliability, its personal integrity, its capacity for toleration and for a quiet, humorous boredom with things. The general strike in England, which was not without its alarming aspects, illustrated all these qualities in our people.

Diogenes Laërtius, Lives and Opinions of Eminent Philosophers, Book 5.

The Complete Greek Tragedies: Euripides II: Helen. Hecuba. Andromache. The Trojan women. Ion. Rhesus. The suppliant women by David Grene, Richmond Alexander Lattimore (eds.), Modern Library, 1963, p. 73

Catechism of a Revolutionary (1869)

Philosophy and Living (1939)
Context: Throughout man's career intelligence and charity have been man's distinctive and most valuable assets. One of our early pre-human ancestors is said to have been much like the Spectral Tarsier, a little mammal about the size of a mouse, with long wiry fingers and huge forward-looking eyes adapted for binocular vision. Not by weapons but by correlation of subtle eyes and subtle hands through subtle brain, this creature triumphed. And man himself conquered the world by the same means, by attention, by discrimination, by skilled manipulation, by versatility; in fact by intelligence and imagination in adapting himself to an ever-changing environment.

Vol. 2, Ch. 25, sect. 298
Parerga and Paralipomena (1851), Counsels and Maxims

Theophrastus, 10.
The Lives and Opinions of Eminent Philosophers (c. 200 A.D.), Book 5: The Peripatetics

Self-Culture (1838)

Variant: Time is the most precious gift in our possession, for it is the most irrevocable.
Source: As quoted in LIFE magazine (22 April 1957), p. 152; also in Letters and Papers from Prison (1967), p. 47.
Context: Time is the most precious gift in our possession, for it is the most irrevocable. This is what makes it so disturbing to look back upon the time which we have lost. Time lost is time when we have not lived a full human life, time unenriched by experience, creative endeavor, enjoyment, and suffering. Time lost is time not filled, time left empty.